Self-assembled InGaAs tandem nanostructures consisting of a hole and pyramid on GaAs (311)A by droplet epitaxy

We report on the fabrication self‐assembled tandem (pyramidal‐ holed) InGaAs nanostructures on GaAs (311)A in comparison with the nanostructures on (100) surface. Under an identical growth condition, the fabricated nanostructures are characteristically dissimilar; ring‐shaped nanostructures on GaAs (100) and pyramidal‐holed nanostructures on (311)A. The underlying formation mechanism of these interesting nanostructures can be understood in terms of intermixing, dissolution of GaAs substrate and surface diffusion driven by a surface reconstruction. The size and density of nanostructures can be controlled by modifying the droplet size, density, and thermal energy applied during the fabrication of droplets and nanostructures. These unique InGaAs nanostructures can offer promising applications in optoelectronics.